Textile-to-mortar bond behaviour in lime-based textile reinforced mortars

Abstract

Lime-based textile-reinforced mortars (TRM) have recently found a growing interest for repair and strengthening of masonry and historical structures. Despite extensive experimental and numerical investigations performed in the last years on the performance of these composites, there is still a lack of fundamental understanding of the fabric-to-mortar bond behaviour (as one of the main mechanisms affecting the cracking and nonlinear response of these composites) and the parameters affecting that. This paper, aimed at addressing this gap, presents a comprehensive experimental and analytical investigation on how the test setup, embedded length, load rate, mortar age and fabric configuration affect the bond behaviour in lime-based TRMs. In total 160 pull-out tests are performed on a glassbased and a steel-based TRM commonly used for strengthening of masonry structures. The results contribute to standardization of the test procedures for characterization of the fabricto-mortar bond behaviour, to fundamental understanding of this mechanism and to optimization of the design of these composites for enhancing their mechanical response.

A multi-level investigation on the mechanical response of TRM-strengthened masonry

“…This observation recalls that the maximum strength of the utilized lime-based mortars does not reach its peak value after 28 days, as opposed to cementitious mortars [41]. In another study conducted by authors [36], the compressive strength of mortar M1, which was cured only one day under plastic and then stored in the environmental lab (20 °C and 60% RH), reached 7.07 and 7.84 MPa for 28 and 90 days, respectively. These values are 12.0 and 16.8 MPa in this work, being 1.7 and 2.1 times that of the previous study.…”

“…The tests were performed using a servo-hydraulic system with a maximum capacity of 25 kN and a mechanical clamp that pull the epoxy resin from the top. In another study conducted by the authors [36], displacement rate effects on the pull-out response of glass-based TRM were investigated. The results illustrated that the bond behavior did not show any considerable changes by increasing the rate from 0.3 to 1.0 mm/min.…”

Mechanics and durability of lime-based textile reinforced mortars

“…This requires accurate measurement of the fibre slip (at both loaded and free ends of the sample) and the strain/stress distribution of the fibre along its embedded length. However, due to the complexity of measurement of the fibre slip at the free end or lack of equipment for measurement of strain distribution along the embedded length, only the fibre slip at the loaded end has been measured and reported in the existing studies [20,21,34].…”

“…As mentioned before, the existing literature on pull-out response of TRM composites used for strengthening of masonry structures is still very limited. Recent studies have shown the important role of fabric configuration (unidirectional/bidirectional), loading rate (in the quasi static range), embedded length and mortar age (at the time of testing) on the pull-out response and bond behaviour of a limited number of existing commercial TRM types [20,21,34]. While there is a need for future studies on other TRM types, the unaddressed role of textile chemical/physical properties, configuration and texture (type of connection at the junctions, grid spacing, etc.…”

Bond Behavior of Steel Cords Embedded in Inorganic Mortars

“…Much of the existing literature has focused on examining the bond performance of SRG systems to a masonry [ 22 , 23 , 24 ] or concrete substrate [ 25 , 26 ]. However, although the quality of bond between the textile and the mortar can critically affect the composite behavior of elements strengthened with these systems in terms of stiffness, ultimate capacity and failure mode [ 16 , 27 , 28 ], only limited work has investigated the interaction at the fiber-to-mortar interface [ 29 , 30 , 31 ]. This study addresses this research gap and examines the bond developed between steel cords and the surrounding inorganic mortar matrix at the mesoscale, as to gain invaluable insights into the intrinsic properties of SRG systems.…”